Abstract. The central-southern section of Chile is defined as one of the Latin
American hot spots in the last IPCC Report due to the impact of glacier
retreat on water resources, the transitional character of the climate, and
its importance in terms of agricultural and forestry activities. In order to
provide a better understanding of glacier behavior in this zone, this paper
analyzes the volumetric changes of glaciers in the Sierra Velluda, located
in the upper Bío Bío River Basin. Bibliographic sources, satellite
images, and DEMs were used to estimate frontal, areal, and volumetric
changes. An analysis of significance was performed in order to provide
accurate estimations of the fluctuations. The results indicate that Sierra
Velluda glaciers have suffered a significant reduction since the 1960s,
despite some short periods of positive fluctuations. A maximum position of a
glacier for the year 1828 was identified, which is in concordance with other
proxies registered elsewhere in Chile. These changes agree with measurements
of glacier fluctuation elsewhere in Chile. While short-term fluctuations are
consistent with the inter-annual precipitation variability, lake levels
records, and a warm phase of the El Niño Southern Oscillation (ENSO),
the general shrinkage agrees with the shift of the ENSO (PDO) in 1976.
Therefore, it is proposed that Sierra Velluda's glaciers are highly
sensitive to high frequency climatic fluctuations and even to inter-annual
variability. Considering that models project a reduction in Andean
precipitation and an altitudinal increase in the 0 °C isotherm, these
ice bodies are expected to continue to shrink.